32 Questions
Who is known as the 'Father of Modern Genetics'?
Gregor Mendel
What term refers to alternative versions of a gene?
Alleles
In genetics, what does 'homozygous' mean?
Having a pair of identical alleles for a character
What is the era of molecular genetics characterized by?
Understanding gene expression and regulation
Which project marked the beginning of genomics in the 1990s?
Human Genome Project
What is a recessive gene?
No noticeable effect unless both alleles occur in a gamete
What type of organism is said to be homozygous for a gene?
An organism with two identical alleles
In genetics, what term is used to describe an organism with two different alleles for a gene?
Heterozygous
What is the main difference between genotype and phenotype?
Genotype is genetic makeup, while phenotype is physical appearance
Which term describes an individual with a dominant phenotype but unknown genotype?
Heterozygous
Why do traits not always reveal an organism's genetic composition?
Because of the different effects of dominant and recessive alleles
What is the purpose of a testcross in genetics?
To determine the genotype of an individual with a dominant phenotype
What did Mendel refer to as a 'heritable factor' in his experiments with pea plants?
Gene
Which generation resulted from the self-pollination of the F1 hybrids in Mendel's experiments?
F2 generation
In Mendel's experiments, what is the term used for plants that produce offspring of the same variety when they self-pollinate?
True-breeding plants
Which of the following represents the two alleles for a specific gene located on a chromosome?
Locus and gene
What did Mendel call the pattern where one allele determines the organism's appearance and the other allele has no noticeable effect?
Dominant-recessive inheritance
Which of the following best describes the Law of Segregation proposed by Mendel?
The two alleles for a heritable character separate during gamete formation and end up in different gametes.
What did Mendel's Punnett square diagrams help predict in his genetic crosses?
'Possible combinations' of offspring genotypes
'True-breeding' plants were used by Mendel to:
'Self-pollinate' and keep offspring consistent for genetic study.
'Alternative versions of genes' that account for variations in inherited characters are known as:
'Unit factors'
What term did Mendel use to describe the process of mating two true-breeding varieties?
Hybridization
According to Mendel's laws, which of the following statements is true?
Alleles segregate independently during gamete formation.
What is the purpose of conducting a testcross in genetics?
To determine the genotype of a mystery individual.
In a monohybrid cross, what is the probability that a heterozygous plant will produce offspring with the recessive phenotype?
$\frac{1}{4}$
What type of cross helps determine whether two characters are transmitted to offspring as a package or independently?
Dihybrid cross
Which of the following best describes the concept of independent assortment?
Alleles segregate independently, leading to different combinations of traits in offspring.
How does the multiplication rule apply to monohybrid crosses?
It determines the probability of two independent events occurring together.
What distinguishes a dihybrid cross from a monohybrid cross?
Dihybrid crosses show inheritance patterns for two pairs of contrasting traits.
When applying Mendel's laws to genetics, what does it mean for genes to segregate independently?
Each pair of alleles separates into gametes without influencing each other's segregation.
In a testcross, why is it necessary to breed the mystery individual with a homozygous recessive individual?
To determine if the mystery individual is homozygous dominant or heterozygous.
What outcome does Mendel's law of segregation predict?
Each parent passes on one copy of each gene variant to their offspring.
Study Notes
Key Concepts in Genetics
- Gregor Mendel is known as the 'Father of Modern Genetics'.
Genes and Alleles
- Alternative versions of a gene are referred to as alleles.
- A recessive gene is one that will not be expressed if there is a dominant allele present.
- A homozygous organism has two copies of the same allele for a gene.
- A heterozygous organism has two different alleles for a gene.
Molecular Genetics
- The era of molecular genetics is characterized by the development of recombinant DNA technology.
- The Human Genome Project marked the beginning of genomics in the 1990s.
Genotype and Phenotype
- Genotype refers to an organism's genetic composition, while phenotype refers to the physical expression of those genes.
- The main difference between genotype and phenotype is that genotype is the genetic makeup, while phenotype is the physical characteristics.
Testcrosses and Breeding
- A testcross is a cross between an organism with an unknown genotype and a homozygous recessive organism.
- The purpose of a testcross is to determine the genotype of the unknown organism.
- True-breeding plants were used by Mendel in his experiments to ensure a consistent genotype.
Mendel's Laws
- Mendel referred to heritable factors as 'factors' in his experiments with pea plants.
- The F2 generation resulted from the self-pollination of the F1 hybrids in Mendel's experiments.
- Plants that produce offspring of the same variety when they self-pollinate are referred to as 'true-breeding'.
- The Law of Segregation proposes that each pair of alleles separates during gamete formation.
- Mendel's Punnett square diagrams helped predict the outcomes of genetic crosses.
Independent Assortment
- Independent assortment is the concept that genes for different characteristics are sorted independently during gamete formation.
- A dihybrid cross helps determine whether two characters are transmitted to offspring as a package or independently.
- The multiplication rule applies to monohybrid crosses, where the probability of each allele combination is multiplied together.
- Mendel's law of segregation predicts that each allele has an equal chance of being passed on to offspring.
Test your knowledge on genetic vocabulary and Punnett squares with this quiz. Questions include identifying homozygous and heterozygous genotypes, as well as predicting phenotypic ratios of offspring from different genetic crosses.
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